Vat dye dispersions containing polyvinylpyrrolidone



of electrolytes in the paste.

United States Patent VAT DYE DISPERSIONS CONTAINING POLYVINYLPYRROLIDONE Albert E. Moran, Somerville, and Earl Kaplan, North Plainfield, N.J., assignors to American Cyanamid Company, New York, N.Y., a corporation of Maine No Drawing. Filed Feb. 14, 1958, Ser. No. 715,177

13 Claims. (Cl. 8-43) This invention relates to improved vat dye paste compositions, and more particularly, to concentrated vat dye pastes stabilized against loss of fluidity by the incorporation therein of polyvinylpyrrolidone.

Many vat dyestuffs are customarily sold in the form of concentrated aqueous pastes, since in this form, they are more easily handled and more readily used. It is important that such pastes remain fluid in order that they may be transferred from one container to another and more easily be measured out by the user and be more easily dispersible in the dyebath. Often however, such vat dye pastes tend to lose their fluidity and become thixotropic on storage. The average dyer does not have the equipment nor the time to restore the pastes to their original fluidity before use. with the proper equipment, one cannot restore the original fluidity. There is therefore a great need for a good In some cases,even i 2,971,812 Patented Feb. 14, 1961 done is used to remove color from fibers and is known as a highly eifective stripping agent for decolorizing or drastically weakening the color of cellulosic fibers dyed with certain vat, sulfur and direct dyestufls. Aqueous solutions of polyvinylpyrrolidone are known to have a strong aflinity for certain types of dyestuffs in solution, where the combination results in a stable complex between the polymer and the dyestufi, and the dyestufi is so firmly held that no simple way is known to release the color once the complex is formed. In view of these known uses for and properties of polyvinylpyrrolidone, it is most surprising that the incorporation of at least quantities may have deleterious eiiects, such as excessive thickening of the composition. The vat dye pasteswhich are to be used in our invention are the concentrated pastes to be sold by the manufacturer, containing the vat dye in its unreduced or 0x0 form. They must have a minimum of 6% dye solids and more often have from 10' to 20% dye solids. It is in such pastes that the 1 problem of thixotropy arises, since in more dilute susand simple method of maintaining the fluidity in commercial vat dye pastes.

A number of methods have been proposed to overcome thixotropy observed with various vat dye pastes. In some .cases, the use of surface active agents assists in conferring long lasting fluidity. For example, it has been proposed to use trialkylolamine triesters for this purpose. In some cases, improved results .can be achieved by a sufficient recluctionof the concentration However, none of these methods is generally operable, and some of them involve extra expense which is not readily added to the cost of the paste.

We have found that the problem of thixotropy in vat dye pastes can be readily solved by the incorporation therein of at least 0.2% of a polyvinylpyrrolidone. Pastes which include a polyvinylpyrrolidone remain fluid for long periods of time and are thoroughly resistant to thixotropy. Although amounts greatlyin excess of .2%

based on the weight of the paste canbeuse'd. In practice there is little use in goingover 3% of the total paste and as a practical matter, usages considerably below this are usual. V 7

It is most surprising that the presence of polyvinylpyrrolidone has no deleterious efiects on vat dye pastes,

1 such as causing the dye solids to settle out or adversely afiecting the dyeing properties of the paste. Polyvinylpyrrolidone, polymeric N-vinyl-Z-pyrrolidone, is sold under various trade names in the form of solutions of vinylpyrrolidone preparations commercially available are quinone acridones, and the like.

those sold under the names of Plasdone, Hamodyne,

. Periston, Subtosan, Peregal ST, Albigen A, and PW- KZO, PVP-K30, PVP-K40, PVP-K60 and PVP-K90. Polyvinylpyrrolidone is used under these names for a variety of purposes. It' has found application in the trade as thickening agents and in the pharmaceutical field as a replacement for blood plasma in the treatment of shock. The polyvinylpyrrolidone products of commerce are known to combine with various substances and to solubilize them. In the textile field, polyvinylpyrroli- V pensions such as the slurries used in vat dye baths, the

amount of water alone is suflicient to keep the slurry fluid.

The compositions of our, invention include concentrated vat dye pastes containing polyvinylpyrrolidone made from many different types of vat dyes, such as the indanthrones, the indigoid and the thioindigoids, the pyranthrones, the dibenzpyrenequinones, the various dibenzanthrone derivatives, anthraquinone thiazoles, anthra- In the practice of our invention, the polyvinylpyrrolidone can be added to the formulation at any point during the making up of the paste. Also, other materials may be present in small amounts as are commonly used in the art, such as dispersing agents (e.g., alkylated naphthalene sulfonic acids, in which the alkyl group has from'8 to 18 carbons, such as sodium dodecylnaphthalene sulfonate, or sulfonated naphthalene-formaldehyde condensate and sodium lignin sulfate), fungicidal agents (e.g., phenol, sodium chlorinated phenolate, sodium benzoate), and other diluents (e.g., glycerin). The polyvinylpyrrolidone can be used without any other ingredients of the above nature,'but usually is found to give better results when used in conjunction with these ingredients.

An especially useful species of our invention is, a concentrated vat dye paste of a vat dye unstable to high temperature vatting, stabilized against decomposition in vatting by the presence of a cobalt compound and against thixotropy by polyvinylpyrrolidone. The use of such cobalt compounds in stabilizing certain leuco vat dyes to high temperatures is described in Letters Patent 2,690,- 952 to Fordemwalt. The dyes in which these areespecially important are those of the indanthrone class, such as dichloroindanthrone. The cobalt compound 'must be present in at least 15% based on the weight of the dye solids but should not exceed 50% of the weight of dye solids.

This application is a continuation-in-part of our co- 6, 1956, now abandoned.

becomes very thick on prolonged standing.

When a similar paste is made including 2 parts of polyvinylpyrrolidone, the mixture remains fluid after many weeks.

Example 2 A 13.5% paste of (4,5) (4',5) dibenzothioin'digo (Indanthrene Brown RR) is prepared by dispersing dye- "stuif press cake with a high speed stirrerto a' paste 'con tain-ing 17.2 parts of real dye, 1.0 part of alkylated naphthalene sulfonic acid, 4 parts of sodium chloride, 0.20 part of Dowicide B and sufiicient water to makeup 1 parts. On standing at room temperature, this. paste begins to lose its fluidity within a few days.

'When a similar paste is made including 2 parts-polyvinylpyrrolidone, the resultant composition is .fluid for weeks.

Example 3 A paste of dibromopyranthrone is preparedby dispersing a press cake with a high speed stirrerto 'a .paste containing 12.9 parts real dye, 1.0.part of alkylated naphthalene sulfonic acid, 0.6 part sodium benzoate and enoughwater to make up 100 parts. The paste, after standing for 20 hours, becomes thixotropic and will not flow.

When a similar paste is prepared whichfinclu'des 2 .parts polyvinylp'yrrolidonmit is stable for many weeks.

Example 4 A 25% paste of dibenzpyrenequinone (Indanthrene Golden Yellow GK) is prepared by dispersing press cake with a high speed-stirrer, to apaste containing. 14.5 parts real vat dye, 15' parts of glycerin, 0.1 part of Dowicide B, 1.5 parts of alkylated naphthalene sulfonic acid and enough water to make up 100 parts. paste becomes thixotropioand does not flow after standing less than 24 hours.

A similar past which includes lpart polyvinylpyr- .rolidone remains "fluid for many days.

. Example '5 An 18.4% ,paste of Algol Yellow GC (1,2,5;6-fbis (2-phenylthiazblo) anthraquinone) is prepared by dispersing press cake with a high speed stirrer toa, paste containing 9.7 parts real dye, 1.0 part alkylated naphthalene sulfonic acid, 2 parts sodium chloride, 0.6 part"sodinm benzoate and enough water to make up 100 parts.

On standing at room temperature the paste starts to become thixotropic'in a fewdays and will not flow.

A similar paste including 2 parts of polyvinylpyrrolidone is stable "for many weeks.

. :Example 6 A 40% paste ofthe grayvat dyestufi described-in UlSJP-atentNO. 2,456,589ris prepared bydispersingfiye stufifpresscake containing 20"'p'arts"of realilye with '1 part" of "sodium 'lignin' "sulfonat'e, andsufli'cienfwater to 'rnake up 100' pa'rts. After standing for "two .days, it becomes'thixotropic and will not'flow.

The gray vat dyestufi described in the above-mentioned patent is a mixtureof unknown-constituents. his the product obtained by fusing with alcoholic caustid'alkali This "the presence of-an acid binder and acupriferqus .catalyst.

.ing chlorinated benzanthrone containing between 11.5%

and 13.5% of chlorine with one molecular equivalent of alpha-amino anthraquinone in the presence of an acid binder and a cupriferous catalyst.

A similar paste including 3 parts of polyvinylpyrrolidone is stable for many weeks.

Example 7 A paste is prepared bydissolving 'cobaltous chloride hexahydrate and polyvinylpyrrolidone in water: and addlingathe resultingrsolution to an-equal quantity of Yapaste of -3,3-dichloroindanthrone. The resulting .paste has the composition: I

Component: Parts 3,3-dichlorindanthrone 10 Sodium salt of sulfonated formaldehydenaphthalene condensate 0.15 'Phenol 0.25 Glycerine 2.5 Dextrine 1Z0 Polyvinylpyrrolidone 2.0 Cobaltous chloride 2.0 Water 82.1

This paste not'only does not develop thixotropy, but :also

.is stable to vatting at high temperature. Sodium .dodecyl naphthalene sulfonate can be used in place ,of the sulfonated formaldehyde-naphthalene condensate.

:We claim: .1. .A vat dye paste composition comprising .at least 6% of :avatdye, water, and at least 0.2% butnotover 3.0% polyvinylpyrrolidone based on the, total paste weight.

2. The compositions of claim 1 in which :a separate dispersing 1 agent is included.

3. The-compositions of claim 2 in which the dispers- Sing agent is:an alkylated naphthalene sulfonic acid.

4. 'The compositions of claim 3 .in which the .vat dye is 'dibromopyranthrone.

5. The compositionof claim 3..in which the vet dye is dib'enzpyrenequinone.

:6. Thecompositionsof .claim 3-:in which the-.vat dye is 1,2,5,6-bis(Z-phenylthiazolo) i. anthraquinone.

'7. The composition .of claim 3 in which :the:vat:dyestuff is the gray vat dyestutf obtained by fusing-awith'alcoholic ;caustic alkali the mixture 10f secondary amines produced T by condensing "chlorinated .benzanthrone .containing between 11.5% and 13.5%10151 chlorine withone molecular equivalent of -:alpha-aminoi anthraquinone in 8. Thecompositions of claim 3innwhichthe-vatidye -is anindanthronea a r I 9. The compositions disclaim- 8 :inwhich .the; vatzdye is 3,-3 diohloroindan'throne.

10. The composition of claim '9 which-contains; also *at least' 15% 'but not over 50% of a cobalt compound, based on the weight-of the dyestufl.

"lliThe composition comprising 20% '3;3'-dichloroindanthrone, 1.0% "alkylated naphthalene sulfonic acid, 0.5%' phenol, 2% polyvinylpyrrolido'ne and "su'flicient water to makeup 100% 12." The composition of 25; parts of :'dibenzpyrenequinone,-15 parts (if-glycerin, 0.1112111 of .afungicide,

, 1.5-parts of alkylated naphthalene sulfonic acid, 1 part ,polyvinylpyrrolidone, 2.0%

. 82.1%;nvater.

the mixture of secondary amines produced by"coiiden s- 7 5 -zof polyvinylpyrrolidone andsuflic'ient Waterto make up parts.

13. FI he composition comprising 10% 3,3-dichloro- .indanthrone, 0.15 alkylated naphthalene ..sulfonic acid,

0.25% @phenol, 2.5% aglycerine, 1.0% dextn'ne, ..2.0% cobaltous chloride, .and

' (References on following page) v References Cited in the file of this patent UNITED STATES PATENTS "2,671,151: 5 6 v OTHER REFERENCES Hansen et a1.: Polyvinyl Pyrrolidone," Proc. of the Am. Assoc. of Textile Chem. and Colorists, February Lawrence Sept. 18, 1928 Nuesslein Oct. 31, 1933 6 1954- w et 1 7, 1937 Schwartz et 211.: Surface Actlve Agents and Deter- Flett Jun 25, 1940 gents, 1958, Intersci. Pub., New York, pp. 306-307. Studer July 9, 1957 Desirens: The Chem. Tech. of Dyeing and Printing, Petersen Aug. 20, 1957 1948, Reinhold Pub. 00., New York, p. 420. 

1. A VAT DYE PASTE COMPOSITION COMPRISING AT LEAST 6% OF A VAT DYE, WATER, AND AT LEAST 0.2% BUT NOT OVER 3.0% POLYVINYLPYRROLIDONE BASED ON THE TOTAL PASTE WEIGHT. 